Getting arrow spine wrong is expensive. You buy a dozen shafts, realize they’re flying sideways, and you’re stuck with arrows you can’t use. This spine calculator takes your draw weight, draw length, arrow length, and point weight to determine the correct arrow spine before you spend money.
Takes 30 seconds. Saves you from buying the wrong arrows.
What Is Arrow Spine and Why Does It Matter?
Arrow spine is the measurement of shaft stiffness. When you release the string, your arrow flexes and bends around the bow (that’s the physics behind archer’s paradox). Too stiff and it won’t flex right. Too weak and it flexes too much. Either way, your arrow flight suffers and accuracy goes out the window.
Different spine ratings – 300, 340, 400, 500, 600 – measure this flex. Lower numbers mean stiffer shafts. A 300 spine arrow is considerably stiffer than a 500. Heavier draw weights need stiffer arrows to handle the extra force.
🎯 Arrow Spine Calculator
Arrow spine is the measurement of an arrow shaft’s stiffness. When you release, the arrow flexes around the bow (archer’s paradox). Too stiff and it won’t flex properly, flying erratically. Too weak and it flexes too much, also causing poor flight. This calculator uses industry-standard spine charts adjusted for your specific bow setup to recommend the correct spine range. Always verify with manufacturer charts for your specific arrow brand.
How This Arrow Spine Calculator Works
This tool accounts for the factors that determine proper spine: your bow’s draw weight, your draw length, finished arrow length from nock to the end of the shaft, and tip weight. Heavier broadheads or field points create more flex, so you might need a stiffer shaft than the basic spine chart suggests.
Whether you’re shooting a compound bow or recurve, the calculator adjusts recommendations. Traditional shooters need to pay closer attention to spine selection since their bows are less forgiving than compounds.
Related: See Our Beginner’s Guide to Choosing Your First Compound Bow
Once you get your spine recommendation, cross-reference it with manufacturer charts. Easton, Gold Tip, Carbon Express, and Black Eagle all use slightly different measurement systems for their carbon shafts.
Fine-Tuning Your Arrow Setup
The calculator gives you a starting point. Paper tune and broadhead testing will dial it in perfectly. If you’re between two spine options, go stiffer for hunting. A slightly stiffer arrow with a heavier broadhead will still tune and fly consistent, plus you get better penetration.
Check your arrow speed and FOC once you’ve selected your spine. All three factors work together to create an accurate hunting arrow that performs when it counts.
What spine are you shooting? Match your bow or just guessing?
